Anthem Inc., one of the country’s biggest health insurers, has been hit by a major cyberattack that could affect millions of its customers and employees. As news of the large-scale hack broke late Feb. 4, it was already having a ripple effect on Capitol Hill, with a top lawmaker calling on Congress to pass information-sharing legislation in response.

Hackers stole personal information from current and former Anthem members, including Social Security numbers, street and email addresses, and income data, the insurer said a statement that described the hack as “very sophisticated.” The firm said it had seen no evidence that credit card or medical information was compromised.

The hackers penetrated an Anthem database housing the personal information of 80 million Anthem customers and employees, the Wall Street Journal reported.

In a statement, the FBI said it was investigating the Anthem hack and praised the company’s swift response.